Recent progress in microelectronics has promoted the miniaturization of portable telephone components such as transmitters and receivers. This miniaturization has permitted the integration of these components into wrist-carried portable radiotelephones. Batteries are required to provide power for the components in a wrist-carried portable radiotelephone, because it is indeed portable.
Batteries are known to power other wrist-carried portable devices, such as wrist watches. Typically only one small battery is needed to power a wrist-carried portable watch because of low power requirements of wrist-carried portable watches. U.S. Pat. No. 3,971,206 shows two batteries, which power watch circuitry, located in a recess of a continuous flexible band.
Radiotelephones, however, have much higher power requirements. For example, a typical portable cellular radiotelephone is specified to operate at a maximum of 0.6 W. The majority of the power in a radiotelephone is consumed by a radio frequency (RF) transceiver circuitry. The radiotelephone must have enough power for a transmitter to transmit RF signals to a remote base station. The radiotelephone must also have enough power for the receiver to receive RF signals from a remote base station and to wait to receive RF signals in a standby mode of operation. Therefore, radiotelephones need more batteries or larger batteries to provide more power.
In wrist-carried portable radiotelephones, a battery which powers the radiotelephone circuitry is generally shown to be located either in a main case or in a hollow wrist band. U.S. Pat. Nos. 5,265,265 and 5,008,864 each show a battery located in a main case attached to a wrist strap. U.S. Pat. No. 3,032,651 shows several batteries located together in a single hollow wrist clip.
At the present state of development of cellular radiotelephone circuitry, in particular, one battery located in the main case or a few small batteries located together in a single hollow wrist clip does not provide sufficient power to operate the radiotelephone circuitry over a reasonable amount of time. Solving this problem by adding more batteries or larger batteries is difficult to do without adversely affecting the aesthetic appearance of the wrist-carried portable radiotelephone.
Accordingly, there is a need for a battery arrangement suitable for a wrist-carried radiotelephone which provides a reasonable amount of power to operate the radiotelephone circuitry and also has an aesthetic appearance.